agent_ui: Add keybinding and action for worktree toggle (#51092)

This PR adds an action and keybinding to trigger the worktree dropdown
in the agent panel. This is still under a feature flag, so no release
notes yet.

Release Notes:

- N/A
6b64b4c6c1Danilo Leal committed on 3/9/2026, 11:55:16 AM· committed by GitHubparent4abeeda
5 files changedLine totals unavailable